1. Field of the Invention
The present invention relates to an image processing apparatus, a method for controlling the image processing apparatus, and a storage medium.
2. Description of the Related Art
There is a conventional image processing apparatus that can read image data from a storage medium (e.g., a USB flash memory or a memory card) and can perform printing of the read image data. If a user has a storage medium that stores image data beforehand, the user may connect the storage medium to the image processing apparatus to cause the image processing apparatus to perform printing of the image data stored in the storage medium.
For example, the above-described storage medium can store image data captured by a digital camera and image data scanned by a scanner. The image processing apparatus allows a user to perform printing of the image data stored in the storage medium without using any information processing apparatus (e.g., a personal computer (PC)).
As a method for performing halftone processing on image data, screen processing and error diffusion processing are conventionally known.
For example, in a case where image data captured by a digital camera is printed by an electrophotographic printing apparatus, an image quality of a printed product can be stabilized by performing the screen processing. On the other hand, image data scanned by a scanner may include a halftone dot image. The screen processing, if performed on a halftone dot image, may generate a moire. Accordingly, it is desired to perform the error diffusion processing on the image scanned by the scanner. For example, as discussed in Japanese Patent Application Laid-Open No. 2007-136825, there is a conventional printing technique that performs the screen processing on image data.
However, if image processing to be performed on the image data is necessary to determine whether the image data read from a storage medium is an image read by a scanner, it is necessary to install a hardware device (e.g., a dedicated circuit) on the apparatus. A cost of the apparatus may increase. Alternatively, a firmware provided in the image processing apparatus may be used to perform the determination. However, in this case, productivity of the image processing apparatus may deteriorate because it takes longer time to complete the processing.
Another method may allow a user to designate whether the image data is read by a scanner. However, in this case, the user is required to perform manual operations.